Bypass stage: The fuel injector is in the state of stopping the fuel supply, the plunger is pressed at the lowest position, and the thin part in the middle of the plunger hooks the internal oil return path of the injector. At this time, the fuel cools the injector and removes the gas in the oil passage. The injector plunger is always in this state during the work and exhaust strokes of the engine. Metering (oil measurement) phase: When the cam continues to rotate to the intake stroke shortly after the cam profile changes, the plunger rises under the action of the spring, first cut off the inlet and return passages, and the fuel bypass ends. The metering hole starts to measure, and the fuel flows to the oil cup of the injector. At this time, due to the low oil pressure, the diameter of the injection hole is small (≈0.17mm) and will not leak oil. When the plunger is raised to the highest position, the cam profile curve remains stable, and the plunger is at the highest position until the end of the air intake. During the compression stroke, under the action of the cam curve, the plunger slowly descends until it approaches the closed metering hole, and the metering ends. Preparing for the injection phase: After the measurement is completed, the plunger descends to a certain position, a certain pressure is generated in the lower oil cup and oil passage, causing the check ball valve to fall on the ball seat, closing the oil passage, and the plunger continues to descend Separating the oil passage from the oil cup, because the engine speed is high and the measuring time is short, its oil cup will not be filled with fuel. Therefore, at this stage, only the gas in the oil cup is compressed and partially excluded in preparation for injection. Injection phase: When the compression stroke of the engine is nearing its end, the cam profile curve changes suddenly, causing the plunger to descend rapidly, and injecting the fuel in the oil cup into the cylinder at a high pressure of 1056KG / CM², while injecting, The thin part in the middle of the plunger makes the inlet and return channels communicate, the fuel starts to bypass, the plunger finally falls on the oil cup, and the fuel injection ends.

How to adjust the injector and valve clearance of Cummins diesel engine

How to adjust the nozzle and valve adjustment of each model of Cummins series engine

3. There are no liners for the cylinder liner, valve seat, valve guide and camshaft, but there is room for inserting the liner.

4, widely used simple structure, small size accessory assembly.

The 6BT diesel engine is composed of 2 mechanisms and 4 systems, such as a crank link mechanism, a valve distribution mechanism, a supply system, a lubrication system, a cooling system, and a starting system.

Note: The main bearing and cylinder head bolts are tightened in sequence from the middle to both sides. After the assembly is completed, each part must be rotated flexibly, and the gaps meet the maintenance standards.

Valve adjustment sequence number

Cylinder number

1

2

3

4

5

6

First cylinder compression top dead center

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Sixth cylinder compression top dead center

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Dongfeng Cummins 6C series engines are different from 6B series engines. The cylinder liner is changed to wet cooling, and the valve seat and valve guide can be exchanged.

How to determine the top dead center of a cylinder: The usual method is to insert the engine timing pin into the hole on the camshaft gear. Make sure to insert it. Mark any place on the shock absorber and turn it 360 degrees. Top dead center on six cylinders.

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